The metal 45 gallon drum has long been a standard industrial container. There have been a number of attempts in the past to replace the steel in the drum with various polymers. Particularly, there has been a desire to replace the steel with olefin polymers and in particular polyethylene. One of the difficulties which has been noted with polyethylene is the difficulty in decreasing the crystal size. While crystal size may be decreased in other polymers using nucleating agents, the crystal size in polyethylene does not seem to be significantly affected by the presence of nucleating agents. As a result, large blow molded containers of polyethylene tend to lack the desired combinations of stiffness and toughness (e.g. being tough but flexible as opposed to brittle). This results in limitations with regard to the number of polyolefin drums which may be stacked upon each other and also a tendency of the filled containers to break or split when dropped from a height of less than about 10 feet (3 meters).
To the best of Applicants' knowledge this drawback has not been solved.
U.S. Pat. No. 5,198,484 issued Mar. 30, 1993 to Michael J. Mannion, assigned to Milliken Research Corporation discloses the use of derivatives of sorbitol and xylitol as clarifying agents in polyolefins and in particular polyethylene and polypropylene. The patent teaches that the bubbles may be reduced in products fabricated from polyolefins containing such agent by dissolving the "clarifying" agent in the polyolefin at a temperature of at least 170.degree. C. However, the patent does not suggest any particular applications in which the polyolefins containing such "clarifying" agents are useful.
The present invention seeks to overcome the existing drawbacks with regard to industrial drums and containers by incorporating such "clarifying" agents into the polyolefins used to manufacture such containers.